Other Comprehensive Earnings/Losses (Changes in Each Component of Accumulated Other Comprehensive Losses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 14,466	$ 15,798	$ 14,789	$ 15,380
Other comprehensive earnings (losses), net of deferred income taxes	244	(382)	145	(137)
Ending balance	10,637	15,496	10,637	15,496
Accumulated Other Comprehensive Losses [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(2,646)	(1,652)	(2,547)	(1,897)
Other comprehensive earnings (losses) before reclassifications	285	(512)	116	(289)
Deferred income taxes	(65)	107	(28)	57
Other comprehensive earnings (losses) before reclassifications, net of deferred income taxes	220	(405)	88	(232)
Amounts reclassified to net earnings (losses)	31	29	78	127
Deferred income taxes	(7)	(6)	(21)	(32)
Amounts reclassified to net earnings (losses), net of deferred income taxes	24	23	57	95
Other comprehensive earnings (losses), net of deferred income taxes	244	(382)	145	(137)
Ending balance	(2,402)	(2,034)	(2,402)	(2,034)
Benefit Plans [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(2,110)	(1,752)	(2,168)	(1,839)
Other comprehensive earnings (losses) before reclassifications	0	0	0	0
Deferred income taxes	0	0	0	0
Other comprehensive earnings (losses) before reclassifications, net of deferred income taxes	0	0	0	0
Amounts reclassified to net earnings (losses)	35	50	113	168
Deferred income taxes	(9)	(11)	(29)	(42)
Amounts reclassified to net earnings (losses), net of deferred income taxes	26	39	84	126
Other comprehensive earnings (losses), net of deferred income taxes	26	39	84	126
Ending balance	(2,084)	(1,713)	(2,084)	(1,713)
ABI [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(542)	106	(374)	(54)
Other comprehensive earnings (losses) before reclassifications	290	(513)	108	(288)
Deferred income taxes	(67)	107	(28)	57
Other comprehensive earnings (losses) before reclassifications, net of deferred income taxes	223	(406)	80	(231)
Amounts reclassified to net earnings (losses)	(4)	(21)	(35)	(41)
Deferred income taxes	2	5	8	10
Amounts reclassified to net earnings (losses), net of deferred income taxes	(2)	(16)	(27)	(31)
Other comprehensive earnings (losses), net of deferred income taxes	221	(422)	53	(262)
Ending balance	(321)	(316)	(321)	(316)
Currency Translation Adjustments and Other [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	6	(6)	(5)	(4)
Other comprehensive earnings (losses) before reclassifications	(5)	1	8	(1)
Deferred income taxes	2	0	0	0
Other comprehensive earnings (losses) before reclassifications, net of deferred income taxes	(3)	1	8	(1)
Amounts reclassified to net earnings (losses)	0	0	0	0
Deferred income taxes	0	0	0	0
Amounts reclassified to net earnings (losses), net of deferred income taxes	0	0	0	0
Other comprehensive earnings (losses), net of deferred income taxes	(3)	1	8	(1)
Ending balance	$ 3	$ (5)	$ 3	$ (5)